Removable bottom hole choke



y 1944- P. COONROD I REMOVABLE BOTTOM HOLE CHOKE Filed April 20, 1942 2 Sheets-Sheet l 45 INVENTOR.

Paul coonr'od BY 770.

A T TORNE K July 18, 1944. P. COONROD REMOVABLE BOTTOM HOLE CHOKE Filed April 20, 1942 Fig. 4.

)8 Fig. 3. 2

2 Sheets-Sheet 2 fir? Q/za.

O "-/2 i o G6 i A l INVENTOR. Paul Coonrod ATTORNEY Patented July 18, 1944 UNETED STATES i A'i'ENT OFFICE 7 2,353,652 REMOVABLE BOTTOM HOLE CHOKE Application April 20, 1942, Serial No. 439,798

Claims.

This invention relates to an apparatus for increasing the production of oil wells and more particularly but not by way of limitation to a means of controlling the inlet of the fluid from the producing strata to a reservoir from which it may be pumped from the well.

In the present day production of oil wells, the water pressure gradient in proximity of the shot hole in many instances becomes so great that considerable more water is produced than oil. It has been found that the use of a choke at the lower end of the tubing string for controlling the flow of inlet oil to be produced, retards the water cone to maintain a layer or film of oil in the shot hole above the Water and thereby prevents a breaking through.

The present invention contemplates the use of a removable bottom hole choke structure disposed in the lower portion of the tubing string and adapted to be secured to the lower end of an insert, or rod pump, or a working barrel arranged at the lower end of the tubing. The fluid to be lifted flows from the sand into the lower end of the tubing, thence through a bypass element and back into the tubing through a choke structure arranged therein. The fluid flows through the choke structure in any predetermined quantity to be discharged into the annulus between the tubing and the casingfor building up the reservoir above a packer arranged at the lower end of the choke nipple.

It is therefore a very important object of this invention to provide a control means at the lower end of the tubing in an oil well which can be inserted or removed through the tubing, thereby eliminating the necessity of a tubing pull job.

A further object of this invention is to increase the production of an oil we11 by creating a constant and uniform how of oil from the shot hole into a reservoir to be pumped, thereby preventing dissipation of the bottom hole pressure of the Well.

And still another object of this invention is to increase the production of oil wells by an apparatus which includes control means arranged in the lower end of the well tubing and maintained therein by creating a balanced pressure for the control means, flowing oil through the control means to build up a reservoir of fluid in the annulus between the tubing and easing.

An additional object of this invention is to provide a removable choke assembly at the end of a tubing string in an oil well which can act as a tubing drain to relieve pressure in a tubing pul1 job.

And still another object of this invention is to increase the production of an oil well by always maintaining a reservoir of oil to be displaced, thereby permitting intermittent pumping or lifting of oil in conformity with present day proration laws, which procedure eliminates considerable pumping time and constant wear and tear on the lifting equipment.

Other objects and advantages of the structure of the invention wil1 be evident from the following detailed description read in conjunction with the accompanying drawings which illustrate two forms of the invention.

Figure 1 is a sectional elevational viewof a well here showing the invention disposed therein.

Figure 2 is a vertical sectional view of the choke unit.

Fig. 3 is a detail view in vertical section of the choking element.

Fig. 4 is a View partly in vertical section, and. partly in elevation, showing another modification of the choke unit.

Referring to Figs. 1, 2, and 3 of the drawings in detail, reference character 2 represents a cylindrical member forming a seating nipple for the control means of the invention. The nipple 2 is adapted to be secured to the lower end of a working barrel housing or to the lower end of the well tubing string 3 in which there is disposed a rod or insert pump (not shown). The seating nipple 2 is disposed in the well bore in proximity of the shot hole 4. Any conventional packing element '6 is arranged between th nipple 2 and the casing 3 above the shot hole, for a purpose as Will be hereinafter described.

Referring to Figures '2, 3 and 4, the choke structure is disposed in the nipple .2 and comprises an upper tubular member In having a plurality of perforations I2. The member ID is fixed to the upper end portion of a cup-carrying body 14 having a floating follower ring Iii slideable on the outer periphery thereof for receiving .a sealing cup as will be hereinafter described. A tube 18 is disposed below and fixed to the body l4 and is provided with a plurality of perforations 20. The upper portion of the tube I8 is provided with female threads 22 adapted to receive male threads 24 of the cylindrical choke or nozzle 26. With the choke 26 secured to the upper portion of the tube i8, it will be seen that it extends through the interior of the body l4 and follower i6 and into the upper cylinder or tube [0. The choke body is provided with asmall axialbore 28 of any predetermined size according to a particular well. Below'the tube I8 and fixed thereto is a duplicate cup carrying body 36 and follower ring 32 but arranged in inverted position. The lower end of the body 36 is provided with a fixedly secured retaining plug 34.

In running the choke structure into the tubing of a well on a rod, insert pump, or the like, the respective follower rings and cup carrying bodies are provided with seating packing cups 36 and 38, respectively. It will be apparent that each of the bodies and rings is provided with shoulder portions 46 adjacent grooves 42 for reception of the packing cups 36 and 38. How

ever, it is to be noted in Figure 2 that the upper and lower sealing cups are disposed in inverted position to each other for a purpose as will be hereinafter set forth.

A baiile or supporting plate 44 is secured by welding, or the like to the interiorof the nipple 2 and closes the lower end portion thereof. In running the choke structure shown in Figure 2 into a well on the end of a tubing or insert pump, the choke unit extends into the nipple 2 with the plug 34 adapted to be seated or be supported by the plate 44. The sealing cups 36 and 38 frictionally engage the inner periphery of the nipple 2. In this position, the perforations I2 of the upper cylinder I are in substantial alignment with perforations 46 provided in the nipple 2. The nipple 2 is provided with an aperture 48 disposed below the plate 44. At a position above the plate 44, the nipple is provided with a plurality of apertures 56. 7 Operation It will be apparent from Figure 2 that the inlet apertures, and apertures 56 are arranged in the nipple within an outer shield 52 secured to the outer periphery of the nipple 2 by welding or the like, and acts as a bypass conduit or passageway for fluid from the well passing through aperture 46, apertures 56 into the interior of the nipple 2. Fluid discharged from apertures 56 flows through apertures 20 disposed in substantial horizontal alignment with the apertures 56. From apertures 26 the fluid is directed through the bore 28 of the choke 26 for limiting or controlling the flow upward into the tubing or casing. Fluid discharged from bore 28 passes through apertures l2 and 46 into the annulus 54 between the tubing and casing to provide a hydrostatic head of well fluid therein. The hydrostatic head creates a reservoir of fluid to be lifted by pumping means (not shown). With a sufficient reservoir, the operation of the pumping means to displace the fluid causes flow back through perforations 46 and l 2, through the pump standing valve 53 secured in the nipple 2 by cups 55. An interconnecting cylinder is fixed to the cylinder I6 and provides communication between valve 53 and cylinder [6. From the above, it will be apparent, that durin the time the reservoir head is building up, there will be no necessity for operating the pump, thereby providing an intermittent pumping action depending upon the reservoir head.

The arrangement of the sealing cups 36 and 38 on the choke unit is always such that the apertures 56 of the nipple is disposed therebetween. This assures flow of well fluid through the apertures 26, and not around the packing cups 36 or 38 or on the opposite side thereof. It will be apparent that fluid flowing through the apertures 56 creates a pressure between the cups 36 and 33 and in order to assure a complete balancing of pressure, and positive maintenance of the choke structure in the nipple 2, the cups 36 and. 38 are inverted with respect to each other. However, in many instances there will be a slight leakage of inlet fluid past the cups 36 and 38. Such leakage past the lower cups 38 is bled off through apertures 56 provided in the nipple 2. Perforations 46 allows for any bleeding due to leakage past the upper cups 36. The bleeder apertures 56 and perforations 46 assure equalization of pressure below the cups. 38 and above the cups 36 as long as the packer 6 is present.

It will be noted that the parts l6, l4, l8 and '36 form a tubular structure within the nipple.

In the event it is desired to utilize the choke structure in a natural flowing well or a well produced on gas lift equipment, or the like, or pumping the well without a packer (wherein the hydrostatic head of fluid acts as a packer), the nipple 2 is disposed on the end of the tubing string, in the manner shown in the preferred embodiment. The modification shown in Figure 4 includes the shield 52 utilized in cooperation with the ports 48 and 56 and baflle plate 44, and a second shield 66 is attached to the outer periphery of the nipple 2a in a position diametrically opposite from shield 52. Within the confines of shield 66 the nipple 2a is provided with upper and lower bleeder ports 62 and 64 arranged on opposite sides of the sealing cups, or at opposite ends of the choke structure for equalizing the pressure. This is necessary since any leakage past cups 36 into chamber 66 would gradually build up an increased pressure in chamber 66 capable of effecting an unsealing of the cups 38. In this modification, fluid enters port 48 and passes through shield 52 and ports 56 into the space 68 between the cups 36 and 38 to be discharged through apertures in tube 18, and the bore 28 of the choke member 26. When the perforations l2, are eliminated, as shown in Fig. 4, the oil is slugged vertically upward through the tubing 3 by natural well pressure or a difierential gas lift um In the modification above disclosed, it will be apparent that utilizing the choke unit in a natural flowing well or a well flowing under gas lift, there is not a pump and attendant sucker rod string for running in and removing from the well. In practice it is then necessary to provide a fishing hook 10, fixed to the upper end of the tubular member I6 and adapted to cooperate with any conventional wire line and jarring tools for running the choke structure into the nipple 2a. In similar manner jarring tools running on a wire line cooperate with the fishing neck 16 for removing the choke structure from the well without the necessity of pulling the well tubing.

In the modification shown in Fig. 4, the fishing head 16 is so constructed as not to interfere with the passage of the liquid upwardly in the tubing from the bore of the choke 26.

Changes may be made in the combination and arrangement of parts as heretofore set forth in the specification and shown in the drawings, it being understood that any modification in the precise embodiment of the invention may be made within the scope of the following claims Without departing from the spirit of the invention.

I claim:

1. In well apparatus of the character described, a tubular nipple designed to be secured to the lower end of a tubing string and to depend therefrom, a baffle plate arranged in the nipple to close the bore thereof to prevent fluid from flowing directly through the nipple, a tubular structure removably positioned in the nipple and having a closed lower end portion resting on said bafiie plate, fluid conducting means extending along'the nipple, lengthwise thereof for conducting well. fluid to the nipple, port means in the nipple placing the upper portion of the fluid conducting means in communication with the interior of the nipple at an elevation above the bafile plate, said tubular structure having port means positioned adjacent to the first mentioned port means for introducing fluid from the nipple into the tubular structure, sealing means arranged between the tubular structure and hipple above and below said first and second mentioned port means, a choke nozzle arranged in the tubular structure and positioned above said second mentioned port means and communicating with the latter, and means at the upper portion of the tubular structure for discharging fluid which has passed through the nozzle, into the nipple, above the upper sealing means,

2. In well apparatus of the character described, a tubular nipple designed to be secured to the lower end of a tubing string and to depend therefrom, a bame plate arranged in the nipple to close the bore thereof to prevent fluid from flowing directly through the nipple, a tubular strucremovably positioned in the nipple and having a closed lower end portion resting on said baffle plate, fluid conducting means extending along the nipple, lengthwise thereof for conducting well fluid to the nipple, port means in the nipple placing the upper portion of the fluid conducting means in communication with the interior of the nipple at an elevation above the bafile plate, said tubular structure having port means positioned adjacent to the first mentioned pert means for introducing fluid from the nipple into the tubular structure, sealing means arranged between the tubular structure and nippic above and below said first and second mentioned port means, a choke nozzle arranged in the tubular structure and positioned above said second mentioned port means and communicating with the latter, means at the upper portion of the tubular structure for discharging fluid which has passed through the nozzle, into the nipple, above the upper sealing means, and second port means in the wall of the nipple below the lower sealing means and above the bafile for discharging liquid from the nipple.

3. In well apparatus of the character described, a tubular nipple designed to be secured to the lower end of a tubing string and to depend therefrom, a balile plate arranged in the nipple to close the bore thereof to prevent fluid from flowing directly through the nipple, a tubular structure removably positioned in the nipple and having a closed lower end portion resting on said baflle plate, fluid conducting means extending along the nipple, lengthwise thereof for conducting well fluid to the nipple, port means in the nipple placing the upper portion of the fluid conducting means in communication with the interior of the nipple at an elevation above the baffle plate, said tubular structure having port means positioned adjacent to the first mentioned port means for introducing fluid from the nipple into the tubular structure, sealing means arranged between the tubular structure and nipple above and below said first and second mentioned port means, said sealing means comprising reversely arranged packing cups, a choke nozzle arranged in the tubular structure and positioned above said second mentioned port means and communicating with the latter, and means at the upper portion of the tubular structure for discharging fluid which has passed through the nozzle, into the nipple, above the upper sealing means.

4. In well apparatus of the character described, a tubular nipple designed to be secured to the lower end of a tubing string and to depend therefrom, a ballle plate arranged in the nipple to close the bore thereof to prevent fluid from flowing directly through the nipple, a tubular structure removably positioned in the nipple and having a closed lower end portion resting on said bafile plate, fluid conducting means extending along the nipple, lengthwise thereof for conducting well fluid to the nipple, port means in the nipple placing the upper portion of the fluid conducting means in communication with the interior of the nipple at an elevation above the baflie plate, said tubular structure having port means positioned adjacent to the first mentioned port means for introducing fluid from the nipple into the tubular structure, sealing means arranged between the tubular structure and nipple above and below said first and second mentioned port means, said sealin means including a collar slidably mounted on the tubular structure and a packing cup secured to the collar, a choke nozzle arranged in the tubular structure and positioned above said second mentioned port means and communicating with the latter, and means at the upper portion of the tubular structure for discharging fluid which has passed through the nozzle, into the nipple, above the upper sealing means.

5. In well apparatus of the character described, a tubular nipple designed to be secured to the lower end of a tubing string and to depend therefrom, a ballle plate arranged in the nipple to close the bore thereof to prevent fluid from flowing directly through the nipple, a tubular structure removably positioned in the nipple and having a closed lower end portion resting on said baflle plate, fluid conducting eans extending along the nipple, lengthwise thereof for conducting Well fluid to the nipple, port means in the nipple placing the upper portion of the fluid conducting means in communication with the interior of the nipple at an elevation abov the baflie plate, said tubular structure having port means positioned adjacent to the first mentioned port means for introducing fluid from the nipple into the tubular structure, sealing means arranged between the tubular structure and nipple above and below said first and second mentioned port means, said sealing means including upper and lower collars slidably mounted on the tubular structure and reversely arranged packin cups secured to the collars, a choke nozzle arranged in the tubular structure and positioned above said second mentioned port means and communicating with the latter, and means at the upper portion of the tubular structure for discharging fluid which has passed through the nozzle, into the nipple, above the upper sealing means.

6. In well apparatus of the character described, a tubular nipple designed to be secured to the lower end of a tubing string and to depend therefrom, a bafileplate arranged in the nipple to close the bore thereof to prevent fluid from flowing directly through the nipple, a tubular structure removably positioned in the nipple and having a closed lower end portion resting on said baffle plate, fluid conducting means extending along the nipple, lengthwise thereof for conducting well fluid to the nipple, port means in the nipple placing the upper portion of the fluid conducting means in communication with the interior of the nipple at an elevation above the baflle plate, said tubular structure having port means positioned adjacent to the first mentioned port means for introducing fluid from the nipple into the tubular structure, sealing means arranged between the tubular structure and nipple above and below said first and second mentioned port means, a choke nozzle arranged in the tubular structure and positioned above said second mentioned port means and communicating with the latter, means at the upper portion of the tubular structure for discharging fluid which has passed through the nozzle, into the nipple, above the upper sealing means, and a standing valve secured to the upper end of the tubular structure and positioned in the nipple.

'7. In well apparatus of the character described, a tubular nipple designed to be secured to the lower end of a tubing string and to depend therefrom, a baffle plate arranged in the nipple to close the bore thereof to prevent fluid from flowing directly through the nipple, a tubular structure removably positioned in the nipple and having a closed lower end portion resting on said baffle plate, fluid conducting means extending along the nipple, lengthwise thereof for conducting well fluid to the nipple, port means in the nipple placing the upper portion of the fluid conducting means in communication with the interior of the nipple at an elevation above the bafile plate, said tubular structure having port means positioned adjacent to the first mentioned port means for introducing fluid from the nipple into the tubular structure, sealing means arranged between the tubular structure and nipple above and below said first and second mentioned port means, a choke nozzle arranged in the tubular structure and positioned above said second mentioned port means and communicating with the latter, means at the upper portion of the tubular structure for discharging fluid which has passed through the nozzle, into the nipple, above the upper sealing means, and port means in the nipple for passing fluid so discharged through the wall of the nip ple.

8. In well apparatus of the character described, a tubular nipple designed to be secured to the lower end of a tubing string and to depend therefrom, a baiile plate arranged in the nipple to close the bore thereof to prevent fluid from flowing directly through the nipple, a tubular structure removably positioned in the nipple and having a closed lower end portion resting on said bafiie plate, fluid conducting means extending along the nipple, lengthwise thereof for conducting well fluid to the nipple, port means in the nipple placing the upper portion of the fluid conducting means in communication with the interior of the nipple at an elevation above the bafile plate, said tubular structure having port means positioned adjacent to the first mentioned port means for introducing fluid from the nipple into the tubular structure, sealing means arranged between the tubular structure and nipple above and below said first and second mentioned port means, a choke nozzle arranged in the tubular structure and positioned above said second mentioned port means and communicating with th latter, means at the upper portion of the tubular structure for discharging fluid which has passed through the nozzle, into the nipple, above the upper sealing means, and means for by-passing liquid from the interior of the nipple below the lower sealing means to the interior of the nipple above the upper sealing means.

9. In well apparatus of the character described, a casing, a tubing string in th casing, a tubular nipple secured to the lower end of the tubing string and depending therefrom, a bafile plate arranged in the nipple to close the bore thereof to prevent well fluid from flowing directly through the nipple, a tubular structure removably positioned in the nipple and having a closed lower end portion resting on said baffle plate, a fluid conducting passageway extending along the outside of the nipple lengthwise thereof, port means in the wall of the nipple below the baflle plate leading from the interior of the nipple into said passageway, second port means in the nipple placing the interior of the nipple in communication with the passageway above th baflle plate, said tubular structure having port means positioned adjacent to the said second port means for introducing fluid from the nipple into the tubular structure, sealing means arranged between the tubular structure and nipple above and below said second port means and the port means in the tubular structure, a choke nozzle arranged within the tubular structure and positioned above the port means in the tubular structure and communicating with the latter, and means at the upper portion of the tubular structure for discharging fluid which has passed through the nozzle, into the nipple, above the upper sealing means.

10. In well apparatus of the character described, a casing, a tubing string in the casing, a tubular nipple secured to the lower end of the tubing string and depending therefrom, a baflle plate arranged in the nipple to close the bore thereof to prevent well fluid from flowing directly through the nipple, a tubular structure removably positioned in the nipple and having a closed lower end portion restin on said baffle plate, a fluid conducting passageway extending along the outside of the nipple lengthwise thereof, port means in the wall of the nipple below the bafile plate, leading from the interior of the nipple into said passageway, second port means in the nipple placing the interior of the nipple in communication with the passageway above the bafile plate, said tubular structure having port means positioned adjacent to the said second port means for introducing fluid from the nipple into the tubular structure, sealing means arranged between the tubular structure and nipple above and below said second port means and the pert'means in the tubular structure, a choke nozzle arranged within the tubular structure and positioned above the port means in the tubular structure and communicating with the latter,

means at the upper portion of the tubular structure for discharging fluid which has passed through the nozzle, into the nipple, above the upper sealing means, and a packer positioned between the casing and nipple.

, PAUL COONROD. 

